Comparative Analysis Of Liquid-based Cytology And Conventional Smear Method To Diagnose Constitutional Lung Cancer In Sputum Samples

Background Lung cancer is one malignant tumor with the most morbidity and mortality of the world, and the morbidity and the mortality are still with an obvious rising trend. Most of the patients with lung cancer arrives already belonged to late, lost surgery cured opportunity. Therefore, it's especially important to looking for effective and feasible early diagnosis and early treatment inspection method, in order to increase the long-term survival rate and reduce fatality rate. The sputum liquid base cytology is one of these early diagnosis approaches with many advantages, e.g. easy to use. safe and painless, noninvasive and repeatable check. This method can be used to systematically observe epithelial cells from atypical hyperplasia to pre-cancerous lesions until the continuous development of infiltrating carcinoma gradient process. It can also examine the recessive lung cancer while the chest imaging technology cannot easily find this. However, although it is one of the principal means of lung cancer early detection, it is rarely used to identify the tumor pathological type.Objective To explore the value of liquid-based cytology test applied to sputum cytology in lung cancer diagnosis.Methods The research object is the 300 suspicious of patients with lung cancer dating from Jun.2009 to Jun.2010. There are shadows in the lung from their chest images and these patients have sputum haemoptysis from the clinical symptoms.300 cases of doubtful primary lung cancer patients who respectively underwent the liquid-based cytology and the conventional smear method were collected and the related pathological data were analyzed. The diagnosis was made by the same pathology panel in double blind way. We compared the two methods to diagnose lung cancer in sensitivity and false-negative. Before the follow-up of these patients ended we have got clear clinical diagnosis。Results 1 The comparison between both positive rates and standard positive rate. There are 30 positive cases in the traditional smear(Phlegm examining rate:10.0%) and 65 positive cases in the liquid base chip(Phlegm examining rate:21.7%).Obviously, the phlegm examining rate of the liquid base chip is higher than the traditional smear. The difference of the detection rate of lung tumor has statistical significance(χ2=4.8,P=0.028). However, both positive rates are below standard positive rate.2 The comparison between both the traditional cytology sputum smear and the liquid base cytology phlegm chip. The detection rate of the liquid base chip is higher than the direct smear, and the sensitivity of liquid base chip is 24%(62/258), specificity is 93% (39/42). which are much higher than the sensitivity 9.3%(24/258) and the specificity 86%(36/42) of traditional smear. These have the statistical significance (χ2=4.1, P <0.05).3 The comparison of the two cytology sputum smear and joint inspection. The phlegmy inspections of traditional cytology and liquid base cytology are carried out simultaneously, where in the traditional smear 30 cases are positive(Detection rate 10.0%).65 positive cases in the liquid-based chip (Detection rate 22%), and 68 positive cases in the joint detection (Detection rate 23%). Obviousely. the joint detection rate is higher than the phlegmy inspection of traditional cytology. These have the statistical significance (χ2=5.45,P=0.030). The joint detection is better than the traditional cytology. The joint detection rate is also higher than the detection rate of the sputum smear of liquid-based cytology. However, this does not have statistical significance (χ2=0.023, P=0.900)4 The comparison of pathologically classified. We adopted theχ2 inspection to compare liquid-based chip and traditional smear in the diagnosis of squamous cell carcinoma (χ2=0.0628,P>0.05), adenocarcinoma(χ2=0.038.P>0.05) and small cell carcinoma (χ2 =0.613,P>0.05).The results show that there is no statistical significance for the difference of the parting diagnostic accuracy.Conclusion Liquid-based cytology method is better than conventional smear in sputum sample detection of lung cancer cell. The former has obvious superiority: combining the two methods, we can detect more lung cancers, so this one is worth of clinical popularization.